Development of a Real-Time Power Grid Monitoring and Fault Localisation System Using Phasor Measurement Units for Nigerian Distribution Networks

Background: Nigeria's electrical distribution network suffers from frequent, poorly localised faults that extend outage durations. Phasor measurement unit technology enables real-time wide-area monitoring and fast fault localisation that can transform grid reliability. Aim: This study developed a real-time power grid monitoring and fault localisation system using phasor measurement units applicable to Nigerian distribution networks. Methods: A prototype PMU was designed using a GPS-synchronised STM32H7 microcontroller and precision ADCs sampling at 128 points per cycle. Phasor estimation was implemented using discrete Fourier transform algorithms meeting IEC 60255-118-1 accuracy classes. Fault localisation was implemented using the two-end impedance-based method on a MATLAB-simulated IEEE 33-bus distribution network representative of a Nigerian state capital network. Results: PMU total vector error met Class P requirements at 0.32%. Fault location error was below 2.5% of total feeder length for single-phase and three-phase faults under simulated conditions. Fault detection time was 28 milliseconds. Communication latency over simulated GPRS links was 110 milliseconds. Conclusion: The developed PMU provides viable real-time monitoring and fault localisation capability for Nigerian distribution networks. Field deployment on pilot feeders and integration with SCADA systems are recommended. Keywords: phasor measurement unit, power grid monitoring, fault localisation, Nigerian distribution network, real-time.